Tube assembly for heat exchanger

ABSTRACT

A tube assembly ( 20 ) for a heat exchanger ( 22 ) and a method of manufacturing the tube assembly ( 20 ) is disclosed herein. The tube assembly ( 20 ) includes a tube ( 32 ) defining a fluid passage ( 46 ). The tube ( 32 ) has first and second sides ( 34, 36 ) spaced from and parallel to each other. A corrugated fin ( 50 ) having alternating ridges ( 52 ) and grooves ( 54 ) is disposed in the tube ( 32 ) between the first and second sides ( 34, 36 ). The corrugated fin ( 50 ) subdivides the fluid passage ( 46 ) into a plurality of passageways ( 56 ). At least one recess ( 58 ) is defined in at least one of the ridges ( 52 ). The recess ( 58 ) extends away from the closest one of the first and second sides ( 34, 36 ) toward an interior of the tube ( 32 ).

BACKGROUND OF THE INVENTION

1. Field of the Invention

The subject invention is related to a tube assembly for a heat exchanger.

2. Description of the Prior Art

Various types of heat exchangers are used in automotive applications. It is known for a tube assembly in a heat exchanger to have a tube that defines a fluid passage and includes first and second sides spaced from and parallel to each other. Such tube assemblies can include a corrugated fin, having alternating ridges and grooves, that is disposed in the tube between the first and second sides, thereby subdividing the fluid passage into a plurality of passageways. Typically these assemblies are held together by braze disposed between the corrugated fin and the tube.

In recent years, the temperatures and pressures of air in heat exchangers has significantly increased, resulting in failure of heat exchangers. In such temperature/pressure conditions, a major disadvantage of prior art designs has been common failures, such as fatigue fracture, of both the tube and the corrugated fin. In prior art designs, specific fractures, such as transverse fractures, may occur, for example, at tube locations, and, in particular, at the inlet header of the heat exchangers. Also, corrugated fin fracture may occur and lead to contamination in heat exchangers.

SUMMARY OF THE INVENTION

In summary, the invention is a tube assembly for a heat exchanger and a method for manufacturing the tube assembly. The inventive tube assembly includes a tube defining a fluid passage. The tube has first and second sides spaced from and parallel to each other. The invention also includes a corrugated fin having alternating ridges and grooves and is disposed in the tube between the first and second sides, thereby subdividing the fluid passage into a plurality of passageways. At least one recess is defined in at least one of the ridges. The recess extends away from the closest one of the first and second sides towards an interior of the tube.

BRIEF DESCRIPTION OF THE DRAWINGS

Advantages of the present invention will be readily appreciated, as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:

FIG. 1 is an exploded perspective view of a heat exchanger utilizing a tube assembly according to an exemplary embodiment of the subject invention;

FIG. 2 is a cross sectional view of the tube assembly shown in FIG. 1 taken along the section line 2-2 of FIG. 1;

FIG. 3 is a perspective view of a corrugated fin according to the exemplary embodiment of the subject invention; and

FIG. 4 is a flow chart of a method for forming the exemplary embodiment of the invention.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENT

Referring to the Figures, wherein like numerals indicate corresponding parts throughout the several views, an exemplary tube assembly 20 is generally shown for use in a heat exchanger 22 in an automobile.

The exemplary heat exchanger 22 includes a first header 24. The first header 24 is typically aluminum, but may be any material known in the art. The first header 24 extends along a first centerline A and defines a plurality of first header tube slots 26 that are spaced along the first centerline A.

The exemplary heat exchanger 22 further includes a second header 28. The second header 28 is typically aluminum, but may be any material known in the art. The second header 28 is spaced from and parallel to the first header 24 and extends along a second centerline B. The second header 28 defines a plurality of second header tube slots 30 that are spaced along the second centerline B and aligned with the first header tube slots 26.

The exemplary heat exchanger 22 further includes a plurality of tube assemblies 20 and each tube assembly 20 includes a tube 32. The tubes 32 are typically aluminum, but may be any material known in the art. Each of the tubes 32 include a first side 34 and a parallel second side 36 that extend between semi-circular first and second edges 38, 40. Each of the tubes 32 extend from a first tube end 42 to a second tube end 44. The ends 42, 44 are received in the first and second header tube slots 26, 30 respectively. Each of the tubes 32 define a fluid passage 46 that extends from the first tube end 42 to the second tube end 44, establishing fluid communication between the first and second headers 24, 28.

The exemplary heat exchanger 22 further includes a plurality of air fins 48 for dissipating heat from the tubes 32. The air fins 48 are typically aluminum, but may be any material known in the art. Each of the air fins 48 are brazed between parallel first and second sides 34, 36 of adjacent tubes 32.

Each of the assemblies 20 further includes a corrugated fin 50. The corrugated fin 50 is typically aluminum, but may be any material known in the art. Each corrugated fin 50 has alternating ridges 52 and grooves 54, and is disposed in one of the tubes 32 between the first and second sides 34, 36. The inserted corrugated fin 50 subdivides the fluid passage 46 into a plurality of passageways 56. The ridges 52 are typically flat or rounded, but may be any configuration.

The assembly 20 includes at least one recess 58 being defined in at least one of the ridges 52. The recess 58 extends away from the closest one of the first and second sides 34, 36. The at least one recess 58 may be any shape known in the art including a rectangular or circular recess 58 a, 58 b. Further, the at least one recess 58 c may extend along an entire length of the corrugated fin 50. Alternative embodiments of the invention can include a plurality of recesses 58, such as at least one recess 58 defined in a plurality of ridges 52 or a plurality of recesses 58 defined in a single ridge 52. A quantity of flux may be disposed only in the recesses 58, or may be disposed the entire length of the ridge 52.

FIG. 4 is a flow chart of a method for forming the exemplary embodiment of the invention. The method begins at 100 and at step 102 the at least one recess 58 is formed in the at least one of the ridges 52 of the corrugated fin 50. Next at step 104, a quantity of flux is disposed in the at least one recess 58. The disposing a quantity of flux in the at least one recess 58 step 104 may further be defined such that disposing flux is only in said recess 58. Next at step 106, the corrugated fin 50 having the alternating ridges 52 and grooves 54 is inserted into the tube 32 to define a plurality of fluid passageways 56. The ridges 52 contact the inner, opposite surfaces of the tube 32. Finally at step 108, the combined corrugated fin 50 and tube 32 are heated after the inserting step 106 to braze the corrugated fin 50 to the tube 32. The method is then over 110.

As such, the corrugated fin 50 has the ability to retain and transport flux as it is inserted in the tube 32. The at least one recess 58 further allows for an even distribution of flux over the tube 32 length which allows for better bonding. With uniform distribution of flux over the tube 32 length, tube 32 failure due to high pressure excursions will be greatly reduced. The at least one recess 58 further allows for a reduced amount of flux to be used. With the at least one recess 58, there is no need to over flux the corrugated fin 50 to compensate for flux lost during the insertion of the corrugated fin 50 into the tube 32. Further, the reduction of flux and the use of at least one recess 58 allow for a reduction in the potential for flux contamination of downstream components due to the excessive application of flux on the corrugated fin 50.

While the invention has been described with reference to an exemplary embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims. 

1. A tube assembly for a heat exchanger comprising: a tube defining a fluid passage and having first and second sides spaced from and parallel to each other; and a corrugated fin having alternating ridges and grooves and disposed in said tube between said first and second sides whereby said fluid passage is subdivided into a plurality of passageways, and wherein at least one recess is defined in at least one of said ridges of said corrugated fin and extends away from a closest one of said first and second sides towards an interior of said tube.
 2. The tube assembly as set forth in claim 1 wherein said at least one recess is rectangular.
 3. The tube assembly as set forth in claim 1 wherein said at least one recess is circular.
 4. The tube assembly as set forth in claim 1 wherein said at least one recess extends along an entire length of said corrugated fin.
 5. The tube assembly as set forth in claim 1 wherein said at least one recess includes a plurality of recesses defined in one of said ridges.
 6. The tube assembly as set forth in claim 1 wherein said at least one recess includes a plurality of recesses, including at least one recess defined in a plurality of said ridges.
 7. The tube assembly as set forth in claim 1 further comprising a quantity of flux disposed substantially only in said at least one recess.
 8. The tube assembly as set forth in claim 1 wherein said ridges are flat or rounded.
 9. A heat exchanger in automobile comprising: a first header extending along a first centerline and defining a plurality of first header tube slots spaced along said first centerline; a second header spaced from and extending parallel to said first header along a second centerline, said second header defining a plurality of second header tube slots being spaced along said second centerline and aligned with said first header tube slots; a plurality of tubes each having a first side and a second side parallel to said first side and each of said sides extending between semi-circular first and second edges and each of said tubes extending from a first tube end to a second tube end and between aligned said first and second header tube slots and each of said tubes defining a fluid passage from said first tube end to said second tube end for establishing fluid communication between said first and second headers; a plurality of air fins each individually disposed between an adjacent two of said tubes for dissipating heat from said tubes; a plurality of corrugated fins each having alternating ridges and grooves and individually disposed in one of said tubes between said first and second sides whereby said fluid passage is subdivided into a plurality of passageways and wherein each of said includes at least one recess defined in one of said ridges and extending away from a closest one of said first and second sides towards an interior of said tube.
 10. The heat exchanger as set forth in claim 10 wherein said at least one recess is rectangular.
 11. The heat exchanger as set forth in claim 10 wherein said at least one recess is circular.
 12. The heat exchanger as set forth in claim 10 wherein said at least one recess extends along an entire length of said corrugated fin.
 13. The heat exchanger as set forth in claim 10 wherein said at least one recesses includes a plurality of recesses.
 14. The heat exchanger as set forth in claim 13 wherein said at least one recess includes a plurality of recesses defined in a single one of said plurality of ridges.
 15. The heat exchanger as set forth in claim 13 wherein said at least one recess includes one or more recesses defined in a plurality of said ridges.
 16. The heat exchanger as set forth in claim 10 further comprising a quantity of flux disposed substantially only in said recess.
 17. The heat exchanger as set forth in claim 10 wherein said ridges are flat or rounded.
 18. The heat exchanger as set forth in claim 10 wherein said first header, said second header, said plurality of tubes, said corrugated fin, and said air fins are aluminum.
 19. A method for manufacturing a tube assembly for a heat exchanger comprising the steps of: inserting a corrugated fin having alternating ridges and grooves into a tube to define a plurality of fluid passageways such that the ridges contact an inner surface of the tube; forming at least one recess in at least one of the ridges of the corrugated fin; disposing a quantity of flux in the at least one recess; and heating the combined corrugated fin and tube after said inserting step to braze the corrugated fin to the tube.
 20. The method as set forth in claim 10 wherein said disposing step is further defined such that flux is disposed on the corrugated fin only in the recess. 